The problem…

For a range of different reasons also called bugs, one or more of the default Windows 10 metro apps that run the new user interface can become corrupt or incorrectly registered so they can no longer be launched and their icon from the Start menu or the task bar cease to display. Instead an empty space or a single-color box and a wired title is all there is left to see in the start menu…

The fix can be performed using Windows Power Shell.

Press Start button and type Type “power shell“

Launch Windows Power Shell from the Start menu as an administrator.

You must then launch Windows Power Shell as an administrator;

The command window will launch. Press Enter once and wait for the prompt to be ready to take a new command:

Right-click in to the Power Shell window to automatically paste the code you jut copied:

Press Enter once again to execute the code:

Some data including defective metro apps related data like savegames or app configurations may be lost by following this procedure.

Let the operation perform and ignore the red errors that will display when finished;

Simply close the Power Shell window and then restart your computer to complete this process.

Alternative solution to this problem:

Create a new Windows 10 user account. You may migrate your data from the old account to the new one afterwards. Also to be able to delete the old account, the new account has to have administrator privileges so you can delete the old administrator account from the newly created account.

Some data including defective metro apps related data like savegames or configurations will be lost. This procedure is recommended only if you consider that is enough to backup only the files and folders to which you have access and then start fresh with all the apps on the newly created user account.